Weight development from age 13 to 30 years and adolescent socioeconomic status: The Norwegian Longitudinal Health Behaviour study

To describe the weight development and model change in body mass index (BMI), and to examine the association of adolescent socioeconomic status (SES) with change in BMI distribution in a cohort followed from adolescence through adulthood. Participants (n = 924) from western Norway were surveyed seven times from age 13 to 30 (1990-2007). BMI was based on self-reported height and weight. Quantile regression analyses were used to model change in weight development and to investigate associations between SES (measured by parental education) and change in BMI distribution. The analyses were adjusted for curvilinearity in BMI development, gender and relevant health behaviours. Body mass index increased over time with the greatest increase in the 90th percentile. No significant associations between change in BMI and SES were observed at any of the percentiles (10th, 25th, 50th, 75th or 90th). Those in the upper BMI percentile gained more weight than those in the lower percentiles indicating that these might need targeted interventions. Further investigation of the association of change in BMI and SES with better quality data might be warranted.